The Philippines
April 5, 2005
A virus for mass destruction of
cutworms
By SBJamias
January 2005 UPLB HORIZON Vol.7, No.1
Development workers attest that if a technology was developed
for and with a farmer, it will be easily adopted and diffused
throughout the community. And within the community emerges a
farmer-leader, who by his natural curiosity, innate knowledge
(we term indigenous technical knowledge), progressive thinking,
experience, and daring, can help transform a village. Such is
the case of 62-year-old Ka Modesto Gabriel, a hard-working and
successful rice-eggplant farmer in Barangay Bantug, a farming
village in Asingan, Pangasinan.
Tagged as the 'eggplant country', Asingan used to produce the
biggest and the best eggplants. Pangasinan produces about 31
percent of the country's yearly harvest of more than 180,000
metric tons of eggplant-the most popular vegetable in the
Filipino diet.
Ka Modesto wielded political clout and social influence in the
village as a 'perennial' chairman of the 150-strong Bantug
Samahang Nayon Multi-Purpose Cooperative (BSNMPC). Thanks to his
rallying efforts in 2000, researchers of the National Crop
Protection Center (NCPC), led by project leader Mr. Mario
Navasero, easily taught the villagers how to monitor the pest
populations in their farms as basis for an Integrated Pest
Management (IPM) system for eggplant.
But even progressive-minded farmers can have stubborn moments.
That same year, Mr. Navasero broached to Ka Modesto the use of
biopesticide, Spodoptera litura Nuclear Polyhedrosis virus
(SINPV), to control cutworms. This was meant to reduce or even
cut his costly spraying of chemical insecticides two times a
week just to produce a marketable yield. Many other farmers
sprayed a mixture or 'cocktail' of chemical pesticides everyday!
Ka Modesto was lukewarm about the technology.
It took another two years for the patient and equally zealous
Mr. Navasero to re-introduce the technology. And nature itself
intervened to demonstrate its merit.
From Nov. 2002 to March 2003, armies of cutworm (Spodoptera
litura) ferociously attacked Ka Modesto's eggplants. And not
just once, but twice - despite his chemical sprays! The cutworms
first feasted on the leaves, shoots and stems of his eggplants
at their late vegetative stage. Then, they devoured the flowers
and setting fruits of the surviving plants near harvest time.
Alarmed, Ka Modesto began picking out the worms mano-mano (by
hand) as advised by Mr. Navasero. But soon, this became very
tedious, especially under the overlapping canopies of 1,300
eggplants in a 1,000-square meter farm. Desperately losing the
cutworm battle, his fellow farmers abandoned their fields.
As if on cue ('providential,' stresses Mr. Navasero), a
Spodoptera litura NP virus broke out in Ka Modesto's farm.
Miraculously, the dreaded cutworms began dying before his eyes
until their population dropped - without chemical spray. Mr.
Navasero pointed out that it was a 'virus' that killed the
overcrowded cutworms.
"The outbreak is a natural phenomenon when the cutworm
population rises so high. Like the common cold, the virus
spreads faster in a crowded place, thus infecting healthy
cutworms." What amazed the farmer more is that by the wonders of
science, he can actually produce the virus-from the dead bodies
of infected cutworms!
Convinced and humbled, Ka Modesto began learning from Mr.
Navasero how to produce and use SINPV. One week after he sprayed
the diluted mixture on his 13-week-old eggplants, the
destructive cutworm turned sluggish, their greenish brown skins
faded to a murky or gray brown, and they did not feed. After
about two to three days, they died.
Invigorated, Ka Modesto began producing SINPV for his next
cropping. He also experimented a lot. For instance, he was able
to produce the virus from healthy cutworms grown from gabi,
which he fed with eggplant leaves dipped in SINPV suspension.
Some farmers who observed his cut-worm free field also began
collecting infected cutworms for their own use and asked him to
teach them.
Realizing the potential of turning production of the virus into
a livelihood project in the village, Ka Modesto requested Mr.
Navasero to train the cooperative members on how to produce, use
and store SINPV. To him, "SINPV was a simple and 'doable'
technology that I wanted to share with my fellow farmers."
Hence, "although it was not part of the NCPC project, nor did it
have funding, I seized that opportunity to share this useful and
relevant technology in the village," Mr. Navasero recalls. "It
was my conviction and commitment as a scientist to give farmers
a cheap, safe and environment-friendly alternative, thus
empowering them to help revive their eggplant industry."
How the virus kills
"SINPV specifically targets cutworms and kills them by becoming
parasites inside their bodies. Hence, the worm must first ingest
the virus by feeding on contaminated leaves or plant parts," Mr.
Navasero explains. "Scientists have known SINPV to be a
biopesticide, and developed countries have even marketed it as
Spod-X and Spodo-lure, as wettable powder or liquid concentrate,
but testing in the country has been limited to laboratories and
small areas," he points out.
"The virus attacks and rearranges the very cell structure of the
caterpillar, forming 'crystals' which are, basically, inanimate
and incapable of maintaining life," he explains. "Infected
caterpillars excrete these crystalline structures through their
droppings or regurgitated fluids as a sign of stress. When
another caterpillar eats anything these crystals are on, the
virus will multiply in all its internal organs and tissues,
eventually killing it," he adds.
"Since the digestive tract of the caterpillar is alkaline, it
breaks down the crystals, releasing the now-active virus."
However, he assures that the virus is safe to humans, including
other mammals, birds, fishes and non-target insects because
these are acid-based, and thus, cannot mass produce the virus.
Why is a virus more effective than chemical spray? "Cutworms are
hardy, plentiful and stealthy. It is hard to spray on worms that
have a lot of host plants, thus can thrive anywhere, and which
feed voraciously at night on young or newly germinating plants
(thus, defenseless) then ride curled under the soil at daytime,"
explains Mr. Navasero.
How to produce the virus
To produce his first SINPV, Ka Modesto gathered moribund and
dead larvae that were still firm and would not rupture when
touched using a wooden stick. He collected the ruptured and dead
larvae that were too soft by clipping-off the portion of the
leaf containing them into a receptacle. He then macerated the
collected materials using a stick to squeeze out the liquefied
contents. He added about 30 to 50 ml of water and stirred the
mixture for a few minutes.
He then transferred the SINPV suspension into screw-capped
bottles and stored these in the freezer of an ordinary
refrigerator to prevent spoilage and to prolong the viability of
the virus.
To use a spray, Ka Modesto mixed 10 to 15 larval bodies for
every 16L capacity knapsack-sprayer. He labeled each bottle
containing the brownish and foul-smelling liquid with their
concentration (e.g. number of worms). Since the SINPV is quite
sensitive to sunlight, he sprayed in the late afternoon, making
sure to wet the surfaces of his eggplant leaves uniformly. One
week after spraying, many cutworms died and their population
continued to crop even without chemical spray.
Spreading the 'virus technology'
To train about 70 other cooperative members challenged Mr.
Navasero's resourcefulness and strategizing abilities. First, he
and his entomologist-wife, Marcela of the Plant Pest Clinic,
Department of Plant Pathology, rendered their training services
for free,
From Oct. to Nov. 2003, the couple scheduled their 'staggered'
training schedules once a week to coincide with Mr. Navasero's
visit to Barangay Bantug for his project with CropLife
Philippines, Inc. The 'ride-on' free transport was generously
supported by the company's Executive Director, Mr. Simeon
Cuyson.
To reach more farmers, they also trained potential trainors
first, namely, Ms. Crisanta Taganas and Ma. Luisa Jamias, the
manager and the assistant manager of the cooperative,
respectively. Thus, activities and production were sustained
even the experts were not in the area.
Further, to ensure that farmers would have enough host plants
and cutworms for rearing the couple provided free mulberry
cuttings while Ka Modesto offered his gabi plants. The farmers
planted soybean a month before the training started. Mrs.
Navasero also developed a technique of rearing cutworms on
soybean that facilitated mass production in the laboratory. The
farmers provided the rearing cages, some facilities and rearing
media, and became responsible for their safekeeping in the
cooperative.
Because of the community's collective efforts, the BSNMPC
members are now mass producing and using SINPV as a biopesticide
in Narangay Bantug. "They have also improvised methods to
produce more SINPV with least cost, with host plants available
in their locality, and with their existing resources," smiles
Mrs. Navasero.
From being producers, the farmers have become energetic and
dynamic extension workers - sharing the technology with
neighboring villages. The 'maverick project' has likewise
strengthened the linkage among the NCPC-UPLB, the cooperative,
the farmers, and the LGU of Asingan led by Mayor Carlos P.
Reyes, Sr. and the Regional Office of the Department of Agrarian
Reform (DAR). Majority of the trainees, who are beneficiaries of
the DAR's Comprehensive Agrarian Reform Program (CARP), feel a
strong sense of ownership over the project.
Most importantly, for Mr. Navasero, the training gas established
the presence of the University in the province and earned the
trust of the farmers. Throughout the training program, Ka
Modesto never failed to testify about his successful experience
with the SINPV and encouraged the trainees to adopt the
technology. He speaks from the heart: "Technologies like the
SINPV manifests the UPLB researchers' genuine and sincere desire
to help poor farmers like me."
Postcript
Mr. And Mrs. Navasero have also found NPV to be effective
against sasmpaguita pests Mr. Navasero is now collaborating with
Drs. Pablito G. Gonzales and Rizaldo G. Bayot of the NCPC on
using another NPV against tomato fruitworm (Helicoverpa
armigera). Their first trials at UPLB and Majayjay, Laguna
showed that applying Helicoverpa NPV twice for the whole
cropping season (based on monitoring of the pest) protected the
plants as adequately as the weekly spraying done by farmers.
Results are being verified through field trials funded by the
Department of Agriculture's Bureau of Agricultural Research
(DA-BAR). |